Geomorphology and sedimentary processes on the Sloggett Canyon, Northwestern Scotia Sea, Argentina

PALMA, F.I.; BOZZANO, G.; PRINCIPI, S.; ISOLA, J.I.; ORMAZABAL, J.P.; ESTEBAN, F.D.; TASSONE, A.A.

JOURNAL OF SOUTH AMERICAN EARTH SCIENCES

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2021 vol. 107

0895-9811

The southern ArgentineContinental Margin hosts the Tierra del Fuego Submarine Canyon System, locatedin the northwestern Scotia Sea, and formed by 4 main canyons:Valentín, Sloggett, Nueva Canyon, and Wollaston. This region is especially interesting due to its complex tectonicsetting and its proximity to the polar regions where intense bottom currents associated with the ArgentineContourite Depositional System take place. Here, we present for the first time the complete high-resolutionswath bathymetry, 28 m grid size, of the Sloggett Canyon obtained during the YTEC-GTGM 0 cruise on board the ArgentineR/V Austral. This new information allowed us tomake a detailed morphosedimentary description of the architectural elements ofthe canyon and to identify the main sedimentaryprocesses that controlled its formation and evolution together with otheroceanographic, climatic, and tectonic ruling factors. The SloggettCanyon, with a total length of 147 km, starts in the continental shelf with the head area located at 90 m water depth, only8.5 km away from the coast, and ends at 3690 m water depth joining the abyssal Yahgan ´ Basin.It is deeply carved into the continental slope, with 1600 m as the maximum incisionobserved in its middle sector. The canyon head area is characterized by twodifferent tributary systems that act as routing conduits for sedimentsupply from the shelf to the canyon domain. On the western flank, the tributary system is densely spaced with deeply incisedV-shaped valleys that suggest the occurrence of activesediment flows that probably evolve into erosive turbidity currents. On theeastern flank, on the contrary, the tributarychannels are sparse less incised, and U-shaped, suggesting that they are nolonger active. Here, mass wasting processes seem to dominate as evidenced by thepresence of slumping and sliding scars. The canyon valley shows two predominant orientations, NW-SE and NE-SW,with sharp bends of approximately 90◦. These orientations wouldhave been controlled by the lineaments of the West Scotia Ridge and the BeagleChannel Fault System, respectively. Thecompletely surveyed Sloggett Canyon highlights the complexity of the Tierra delFuegocontinental margin, and brings new insight for futuremultidisciplinary research in this region.